Can I share a neutral from multiple strings

[Ryang]

Hi guys

i have a simple caravan setup, 6 panels, 3 strings of 2. Each string is a set of 2 matching panel, but each string is slihtly different panels to each other.

previously I have just wired them back to a common pole (1 for positive and 1 for neutral) and then direct to the mppt as a bundle.

haven’t been getting great output, so I am going to experiment with 3 strings each to it’s own mppt.

can I share a neutral for the 3 strings Or will each scc need its own individual. (Main reasoning being sharing = less holes in the caravan roof).

thanks in advance

 

[12VoltInstalls]

previously I have just wired them back to a common pole (1 for positive and 1 for neutral)

That’s properly called “negative,” neg(-), or some say, “ground” but ground is a certain thing so I stick with ‘negative.’
Neutral is in an AC system and isn’t ‘ground.’

can I share a neutral negstive(-) for the 3 strings Or will each scc need its own individual. (Main reasoning being sharing = less holes in the caravan roof).

theoretically that would work I supppse
I wouldn’t do it, though. It’s also unclear to me if that would mess with the mppt seeking, either.

I would just run all the wires through “gland” shells installed with polyurethane adhesive caulking or lexel. That will be no less water proof than “one fewer hole” if installed properly.

The output of the mppt’s can then be paralleled at a busbar.

 

[mikefitz]

haven’t been getting great output,

With different panels in the string that's a possibility. Suggest testing each string with a meter for output voltage and SC current.
Details of the panels, how they are connected in the string, and the model of solar controler used, and the units intended to add, would be useful in the discussion.
Don't common the negative feeds to individual controllers.